1. Field of the Invention
This invention relates to locking and release mechanisms, particularly for use with beach or patio umbrellas.
2. Discussion of the Known Art
Large beach or patio umbrellas may become dangerous projectiles in the presence of strong winds, if the umbrellas are not properly weighted or anchored to the ground. Serious personal injury and substantial property damage can occur under such circumstances. Accordingly, there is a need for a mechanism or device that will release an opened umbrella canopy to close quickly in the presence of a strong wind, in order to reduce the overall wind force acting on the umbrella to a safe level.
U.S. Pat. No. 6,247,483 (Jun. 19, 2001) discloses an automatic locking and release device for a beach umbrella. The device includes a spring-loaded locking bar that is mounted inside of an umbrella mast for sliding movement through an opening in the mast. A lever is also pivotally mounted inside the mast. One end of the lever contacts an inside end of the locking bar, while an opposite end of the lever has a cam that swings through a slot in the mast a certain distance above the locking bar. In use, when an operating collar or runner on the mast is moved upward to open the umbrella, the runner urges the lever cam into the mast and causes the opposite end of the lever to advance the locking bar out from inside of the mast.
When the runner is released to rest on the locking bar, further downward movement of the runner is blocked by the bar so the umbrella will stay open. When the runner is raised again to engage the lever cam, the opposite end of the lever interacts with the locking bar in such manner that the bar retracts fully into the mast. The runner is then free to descend on the mast without obstruction by the bar, allowing the umbrella to close.
U.S. Pat. No. 2,937,653 (May 24, 1960) relates to a supporting and release catch for the runners of beach umbrellas. Like the '483 patent, the catch of the '653 patent includes a lever that is mounted to pivot inside of an umbrella mast. In a rest position, an arm on an upper portion of the lever projects out through a slot in the mast. When the runner is moved up into contact with the arm, a hook on a lower portion of the lever is swung outside of the mast through a corresponding slot. If the runner is suddenly released, it engages the hook and remains in such a position that the umbrella stays open. If, however, the runner is raised and then slowly lowered on the mast, the lever hook is swung by gravity fully into the mast. The runner is then free to move lower on the mast as the umbrella is closed.
As noted, the mechanisms of the '483 and the '653 U.S. patents are fairly complex and are mounted inside of an umbrella mast. Therefore, the mechanisms can not be easily applied to most conventional, existing beach or patio umbrellas. Moreover, the known mechanisms may not respond quickly enough to ensure that an umbrella runner or collar will descend freely on the umbrella mast and allow an opened canopy to close as soon as a strong wind starts to lift the canopy. Accordingly, there is a need for a safety device that can work with existing beach and patio umbrellas, and respond to potentially dangerous wind conditions by quickly releasing the umbrella runner from an open position at which it is set on the umbrella mast.